What is the importance of the lantern cemetery in the novel, You’ve Reached Sam?

The lantern ceremony that Mika plans is intended to allow her and her friends to have a cathartic release of what they are holding on to. She wants Sam to give them permission to let go and begin moving on and feeling happy again while still loving him. Julie struggles to let go of her lantern, eventually chasing it down and falling short, signifying her inability to continue holding on so fully.